The present invention relates to improvements in automatic parallel parking systems for vehicles such as automobiles, trucks and the like.
Because of the difficulty experienced by many drivers in properly executing a standard parallel parking maneuver, various systems have been proposed for enabling the vehicle to perform such maneuver automatically. For example, Hirsch U.S. Pat. No. 2,906,355 and Odell U.S. Pat. No. 3,669,200 show mechanical linkages powered by the drive train of the vehicle for automatically controlling steering while the vehicle executes the parallel parking maneuver in reverse gear. Such mechanical systems require major modification of the vehicle and are accordingly too expensive to be justified by the additional convenience which they provide. Also, they do not compensate for variables such as the transverse space separating the driven vehicle from the parked vehicle behind which it is desired to park, variations in the longitudinal alignment of the two vehicles at the beginning of the parking maneuver, variations in the width of the parked vehicle or variations in the length of the available parking space.
Another prior automatic parallel parking system, shown in Clements et al. U.S. Pat. No. 3,029,884, controls the standard power steering valve through cam-operated control of a reversible fluid pump which must be added to the system. This system, although utilizing the existing power steering arrangement, likewise requires the addition of substantial mechanical structure to the vehicle at substantial expense, and yet is also incapable of compensating for the variables mentioned above.